tests/genmc/fail/data_race/atomic_ptr_alloc_race.rs

//@revisions: write dealloc
//@compile-flags: -Zmiri-genmc -Zmiri-disable-stacked-borrows -Zmiri-ignore-leaks

// Test that we can detect data races between an allocation and an unsynchronized action in another thread.
// We have two variants, an alloc-dealloc race and an alloc-write race.
//
// We never deallocate the memory, so leak-checks must be disabled.
//
// FIXME(genmc): The error message is currently suboptimal, since it mentions non-allocated/freed memory, instead of pointing towards the missing synchronization with the allocation.

#![no_main]

#[path = "../../../utils/genmc.rs"]
mod genmc;

use std::alloc::{Layout, alloc, dealloc};
use std::sync::atomic::AtomicPtr;
use std::sync::atomic::Ordering::*;

use crate::genmc::*;

static X: AtomicPtr<u64> = AtomicPtr::new(std::ptr::null_mut());

#[unsafe(no_mangle)]
fn miri_start(_argc: isize, _argv: *const *const u8) -> isize {
    unsafe {
        let ids = [
            spawn_pthread_closure(|| {
                let a: *mut u64 = alloc(Layout::new::<u64>()) as *mut u64;
                X.store(a, Relaxed); // Relaxed ordering does not synchronize the alloc with the other thread.
            }),
            spawn_pthread_closure(|| {
                let b = X.load(Relaxed);
                if !b.is_null() {
                    if cfg!(dealloc) {
                        // Variant: alloc-dealloc race
                        dealloc(b as *mut u8, Layout::new::<u64>()); //~[dealloc] ERROR: Undefined Behavior
                    } else {
                        // Variant: alloc-write race
                        *b = 42; //~[write] ERROR: Undefined Behavior
                    }
                }
            }),
        ];
        join_pthreads(ids);
        0
    }
}